In the field of intravascular ultrasound devices, it is generally known to mount an ultrasound transducer on the tip of a catheter to form a radial ultrasound image e.g. of a blood vessel or the surrounding tissue. The ultrasound transducer elements may be rotated in order to emit and receive ultrasound waves in the radial direction of the catheter.
It is further known to replace the mechanically scanning ultrasound transducer elements in the intravascular ultrasound devices by electronically scanning devices having an annular array of ultrasound transducer elements, which are usually formed by piezoceramic transducers and which may be replaced in future applications by capacitive micro-machined ultrasound transducers (CMUT). These capacitive micro-machined ultrasound transducers are manufactured on the basis of a silicon wafer by means of IC process technologies and can be manufactured with low costs and can be scaled down to the dimensions of an intravascular ultrasound transducer.
For manufacturing an annular ultrasound transducer, a semi-flexible ultrasound transducer array is formed on the basis of a silicon wafer substrate that is optionally wrapped or bent around and attached to a cylindrically shaped submount structure in order to form the annular array and to transmit and receive ultrasound transducer waves in the radial direction of a catheter. These semi-flexible ultrasound transducer arrays consist usually of several silicon elements comprising ultrasound transducer elements which are connected to each other by a flexible element, so that the rigid silicon elements can be wrapped around a cylindrically shaped submount structure.
A bendable micro-machined ultrasound transducer array, which can be attached to a cylindrical submount structure to form the cylindrically-shaped ultrasound transducer array is known from US 2005/0146247 A2.
An electromechanical transducer including a multiple cellular structure is known from EP 2 441 530 A2, wherein a front silicon film is electrically connected to a rear surface of the multiple cellular structure by means of a via plug.
The silicon elements of the ultrasound transducer, which are flexibly connected have to be fabricated with high precision and the electrical functionality of the integrated ultrasound transducer elements and the electrical circuits have to be guaranteed in order to assure the functionality of the ultrasound transducer array in general.